1. Field of the Invention
The present invention relates to a coupled circulation tube for ball screw unit, in particular, to a circulation tube symmetrically coupled with two half arcuate elbow tubes for ball screw unit so as to simplify the molding die, increase the mechanical toughness, and cut down the production cost.
2. Description of the Prior Art
In a conventional arcuate elbow tube for a ball screw unit, it is formed of two pieces of a first half arcuate elbow tube and a second half arcuate elbow tube parallelly simple contacted together to configure into a hollow snugly curved U shape tube for the rolling balls to circulate smoothly therein.
As the above described U shape elbow tube is parallelly coupled with two half pieces, it is subjected to inevitable and constant impact and collision of balls rolling inside for a long time ultimately resulting in a fatal damage to the operation of the apparatus due to metallic fatigue and scars produced by collision and abrasion of the balls on the inner surface of the circulation tube.
The above mentioned arcuate elbow tube as that to be applied for the circulation tube for a ball screw unit has not yet been able to be formed integrally in one piece. A circulation tube engaged with two half tubes always has a weakness of cracking at the bonding seam so that the basic requirement to assure a certain toughness is beyond one's power. Aiming at the above depicted defects, the present invention is to propose a newly developed coupled circulation tube for ball screw unit capable of eliminating the disadvantages of the conventional product described above.